The invention concerns a ceiling joist formwork system comprising a ceiling table, a vertical support, an inner board, a ceiling joist base and an outer board, wherein the outer board and the ceiling joist base are connected to each other, in particular in a rigid fashion, wherein the vertical support is rigidly mounted to the ceiling table, and wherein the ceiling joist base is mounted to the vertical support.
A ceiling joist formwork system of this type is disclosed in the company brochure “Anwenderinformation Dokamatic-Tisch” (User information Dokamatic-Table), company Doka Industrie GmbH, Amstetten, Austria, December 2005, pages 30-31.
Formwork technology enables the production of almost any structure from concrete, in particular walls and ceilings of buildings. A space is thereby initially delimited to the sides and to the bottom, in which the structure is to be produced (encasing). Formwork elements are used for this purpose. The delimited space is subsequently filled with liquid concrete. After hardening of the concrete, the formwork elements are removed (stripping of the formwork) and the finished concrete structure can be used or further processed.
The ceilings and the supports for the ceilings of many modern buildings are produced from concrete. The ceilings are provided with steel reinforcements in order to accept the loads that are produced. The thickness of the ceiling thereby depends on the load and the desired clear span.
Ceilings are conventionally provided with ceiling joists in order to reduce the thickness of the ceiling and thereby the amount of concrete that is used. A ceiling joist is a steel-reinforced concrete support that extends below the ceiling and is suited to distribute loads and respectively transfer loads to supports or load-bearing walls. A typical ceiling joist is a structure that projects in a downward direction from the ceiling panel at the edge of a ceiling.
A ceiling joist formwork system is required to produce a ceiling joist. The ceiling joist itself is thereby delimited by the form linings of an inner board, of a ceiling joist base and of an outer board. The form lining of the inner board thereby directly joins the form lining of a ceiling table.
An “edge table with ceiling joist” is disclosed in the company brochure “Anwenderinformation Dokamatic-Tisch”. A ceiling joist butt strap is rigidly mounted to a ceiling table and an inner board is rigidly connected to the ceiling joist butt strap. A horizontal locking bar is also rigidly mounted to the ceiling joist butt strap, to which locking bar, in turn, a ceiling joist base is rigidly mounted as well as an outer board that can be hinged away.
The inner board of this conventional ceiling joist formwork system is normally stripped by lowering the ceiling table that is rigidly connected to the inner board. The inner board is thereby simultaneously separated from the finished concrete wall of the ceiling joist. A considerable force thereby acts on the inner board such that the inner board might be deformed or otherwise damaged. For this reason, the inner board must be frequently repaired or replaced. In order to prevent damage to the inner board, the inner board of the conventional ceiling joist formwork system would have to be initially separated from the ceiling table and be separately stripped which is, however, quite cumbersome and labor-intensive.
It is the underlying purpose of the present invention to provide a ceiling joist formwork system that facilitates stripping, in particular of the inner board, and reduces the risk of damage to the inner board.